English

A census of compact sources at 162MHz: first data release from the MWA Phase II IPS Survey

Instrumentation and Methods for Astrophysics 2023-01-04 v1 Astrophysics of Galaxies

Abstract

We present a catalogue of over 7000 sources from the GLEAM survey which have significant structure on sub-arcsecond scales at 162MHz. The compact nature of these sources was detected and quantified via their Interplanetary Scintillation (IPS) signature, measured in interferometric images from the Murchison Widefield Array. The advantage of this approach is that all sufficiently compact sources across the survey area are included down to a well-defined flux density limit. The survey is based on \sim250×\times 10-minute observations, and the area covered is somewhat irregular, but the area within 1hr<RA<11hr; 10<-10^\circ<Decl.<+20<+20^\circ is covered entirely, and over 85% of this area has a detection limit for compact structure below 0.2Jy. 7839 sources clearly showing IPS were detected (>5σ>5\sigma confidence), with a further 5550 tentative (>2σ>2\sigma confidence) detections. Normalised Scintillation Indices (NSI; a measure of the fraction of flux density coming from a compact component) are reported for these sources. Robust and informative upper limits on the NSI are reported for a further 31081 sources. This represents the largest survey of compact sources at radio frequencies ever undertaken.

Keywords

Cite

@article{arxiv.2210.05400,
  title  = {A census of compact sources at 162MHz: first data release from the MWA Phase II IPS Survey},
  author = {John Morgan and Rajan Chhetri and Ron Ekers},
  journal= {arXiv preprint arXiv:2210.05400},
  year   = {2023}
}

Comments

20 pages, accepted for publication in PASA